Motor switch operating mechanism for calculating machines



MOTOR SWITCH OPERATING MECHANISM FOR CALCULATING MACHINES May 14, 1957E. M. LIPPERT EI'AL 8 Sheets-Sheet 1 Original Filed Sept. 20, 1951 iii wm M4,? 5

y 14, 1957 E. M. LIPPERT El AL 2,792,176

MOTOR SWITCH OPERATING MECHANISM FOR CALCULATING MACHINES Original FiledSept. 20, 1951 8 Sheets-Shut 2 H ww Q J p J :3 a E; 4 SJ h I a Q a l 213 a C 0 i N 3; %f C I J n INVHVTOR$-' [rlard "flfllipperf Ralph Z.Sckuliz Alb! rfur fezdt May 14, 1957 E. M. LIPPERT E'T'AL 2,792,175

MOTOR SWITCH OPERATING MECHANISM FOR CALCULATING MACHINES OriginalFiled. Sept. 20, 1951 8 Sheets-Sheet 3 INVENTI'ORS:

Ir]; ard M. [zpperi y 14, 1957 E. M. LIPPERT EIAL 2,792,176

MOTOR SWITCH OPERATING MECHANISM FOR CALCULATING MACHINES Original FiledSept. 20, 1951 8 Sheets-Sheet 4 )SUBTOL INVENTORS. Erhard [ipperf May14, 1957 E. M. LIPPERT ETAL MOTOR SWITCH OPERATING MECHANISM FORCALCULATING MACHINES 0ri .ginal Filed Sept. 20. 1951 8 Sheets-Sheet 5 M0701? 71? ON T0711 50508-707 OPIIJf/OW- GO'I'INOR MOM WEI! INVENTORS.Erhard MLZipperf Ralph L. Schultz Mlberf VM /feldf May 4, 1957 E. M.LIPPERT ETAL 2,792,176

MOTOR SWITCH OPERATING MECHANISM FOR CALCULATING MACHINES Original FiledSept. 20, 1951 v 8 Sheets-Sheet 6 7'0 PRIVIITZISTdI/A/6 7'0 lVlI/TKILPas/1'10.

' F l L.8 huli E5511. lslz Kmyfalt May 14, 1957 E. M. LIPPERT EI'AL 5MOTOR SWITCH OPERATING MECHANISM FOR CALCULATING MACHINES Original FiledSept. 20, 1951 8 Sheets-Sheet 7 NORMAL Pas/71a V/[WID FRO/H P16!!! SIDEOF MIClI/NE NORM/1L POSITION VIEWE FROM LIP! SIDE INVENTORS. Erhard 0i.Zipper! Falpfi acfiulfz MIMI? KMJ/fldt May 14, 1957 E. M. LIPPERT ETALMOTOR SWITCH OPERATING MECHANISM FOR CALCULATING MACHINES Original FiledSept. 20, 1951 8 Sheets-Sheet 8 SIGNAL SECTOR l/V 19/6 Pf/AT/A/GPOSITION I INVENTOR$-' [Mord 0X. lip turf gulp/1 l. Schultz UnitedStates Patent MOTOR SWITCH OPERATING MECHANISM FOR CALCULATING MACHINESErhard M. Lippert, Ralph L. Schultz, and Albert V. Neyfeldt, Chicago,llh, assignors to Victor Adding Machine Co., Chicago, ISL, a corporationof Illinois Original application September 20, 1951, Serial No. 247,491,now Patent No. 2,731,206, dated January 17, 1956. Divided and thisapplication April 21, 1955, Serial No. 504,936

2 Claims. (Cl. 235-62) Our invention relates generally to calculatingmachines, and more particularly to improved control and operationregistering mechanism.

it is an object of the invention to provide an improved mechanism toinitiate an operating cycle of the machine in response to operation ofany one of several of the function control keys.

Other objects will become apparent from the following description,reference being had to the accompanying drawings, in which:

Fig. 1 is a right side elevational view of the machine, with a portionof the casing removed;

Fig. 2 is a plan view of the machine, taken generally on the line 2-2 ofFig. 1;

Fig. 3 is a fragmentary vertical sectional view, taken on the line 3-3of Fig. 2, showing the plus and minus key interlocks and the mechanismthrough which the motor switch is operated by the plus key;

Fig. 4 is a view similar to Fig. 3, with the minus key depressed;

Fig. 5 is a view similar to Fig. 3, showing the parts in total takingposition;

Fig. 6 is a view similar to Fig. 3, showing the parts in non-addposition;

Fig. 7 is a perspective view of the mechanism for operating the motorswitch during total and subtotal operations;

Fig. 8 is a fragmentary perspective view, showing the manner in whichthe motor switch operating mechanism is controlled during a non-addoperation;

Figs. 9 to 12 are fragmentary vertical sectional views, taken on theline 99 of Fig. 2, showing the mechanism for latching the total key inpartly operated position, for moving it to fully operated position, andfor preventing the total key from being latched when the hood of thecasing is raised;

Fig. 13 is a fragmentary sectional view, taken on the line 13-13 of Fig.2, showing the manner in which the operation indicating signal printingsegment is operated;

Fig. 14 is a fragmentary vertical sectional view, taken on the line14-14 of Fig. 2, taken from the left-hand side of the machine, showingthe manner in which the non-add key operates the signal printingsegment;

Fig. 15 is a fragmentary perspective view of a portion of the means forpositioning the signal printing segment;

Fig. 16 is a vertical sectional view showing the means by which thesignal printing segment is positioned by the minus bar;

Fig. 17 is a perspective view of a portion of the mechanism used toposition the signal printing segment upon operation of the non-add keylever;

Fig. 18 is a fragmentary sectional view, taken on the line 1813 of Fig.2, taken from the left side of the machine showing the hood operatedsafety switch; and

Fig. 19 is a schematic wiring diagram of the electrical circuit employedto energize the motor.

"ice v This application is a division of a copending application SerialNo. 247,491, filed September 20, 1951, which on January 17, 1956,matured into Patent No. 2,731,206.

Referring to Figs. 1 and 2, the machine comprises the usual numeral keys20, a plus bar 22, a minus bar 24, a total and subtotal key 26, and anon-add and repeat key 28.

The machine illustrated is operated by an electric motor 36 having asuitable speed governing mechanism 32.

Generally speaking, the machine comprises an outer left side frame plate34, an inner left side frame plate 36, an inner right side frame plate38, and an outer right side frame plate 40. The plus bar 22 is securedto a key stem 42 which is guided for generally vertical movement bythree studs 44, 45, and 46, carried by the frame plate 38, the stemhaving suitable elongated slots for the reception of these studs.Similarly, the minus key stem 47 is guided on studs 45, 46, and 48. Eachof the key stems 42 and 47 has a forwardly projecting lug 50 whichoverlies a stud 52 projecting sidewardly from a rocker lever 54 pivotedon a stud 56 carried by the outer right frame plate 40. The other end ofthe rocking lever 54 has a pin and open end slot connection with anintermediate lever 58 pivoted on a stud 60, and the rearward end of thelever 58 overlies a roller 62 mounted on a switch operating link 64, thelatter being vertically slidable on a pair of studs 66, 67, the linkbeing normally held in its uppermost position by a tension spring 68.

The link 64 has an eccentrically mounted insulating disc 70 forengagement with the leaf spring switch 72 which, as will appearhereinafter, is in the motor energizing circuit.

As best shown in Figs. 3 and 4, a locking arm 78 is pivoted on stud 46,the plus key stem 42 has a sidewardly projecting stud 74, while theminus key stem 47 has a similar sidewardly projecting stud 76. Thesestuds are positioned so as to move locking arm 78 rearwardly when theplus key 22 is depressed, and forwardly when the minus key 24 isdepressed, the locking arm 78 thus preventing the plus and minus keysfrom being depressed at the same time. It will be noted, particularlyfrom Figs. 3 and 4, that the depending portions of the key stems 42 and47 are similarly shaped and operate the lever 54, and hence the motorswitch 72, in the same manner. The locking arm 78 carries a stud 80which, when the arm is swung rearwardly, as by depression of the pluskey, moves a slide 82 rearwardly, the slide being mounted for limitedreciprocation on a pair of studs 84.

When the minus key 24 is depressed, as shown in Fig. 4, the stud 76 onits key stem engages a camming surface 86 on the slide 82 and cams thelatter rearwardly.

The rearward end of the slide 82 has a projection 88 which is inengagement with a stud 90 projecting side wardly from a lever 92 pivotedat "93. The slide 82 also has an upwardly and rearwardly facing cammingprojection 94 which normally contacts a sidewardly projecting stud 96 ona crank 98 pivoted on a shaft 160.

As will appear hereinafter, the arm 92 and crank 98 serve as means forlocking the total and substotal kc and the non-add key, respectively.

The total and subtotal key 26 is mounted on a key stem 102 (Fig. 7), thelatter being pivoted on a stud 104 and biased to its normal centralposition by a tension spring 105. The key stem has a sidewardlyprojecting stud 106 which is slidable in an open end slot 108 formed inan arm 110 which is secured to a sleeve 112. The right-hand end of thesleeve 112 has an arm 114 secured thereto which is similar in shape tothe arm 110. The open end slot in the arm 114 embraces a stud 116projecting sidewardly from a crank 118 which is pivoted on a stud lyingon the same center as the stud 104 upon which the total key stern 162 ispivoted. The crank 113 carries a stud 122 (Fig. 5) which is normally inalignment with a notch 124 in the arm 5 2. However, when the key 26 isswung forwardly, as when conditioning the machine for a total takingoperation, or rearwardly, as when taking a subtotal (as shown in dottedlines in Fig. 5}, the 122 cams the arm 92 forwardly, thereby through thestud and projection 88 of the slide 32, moving the slide forwardly,thereby swinging the locking lever 73 forwardly, the slide and is thuspreventing the depression of either the plus or minus key bar by virtueof the fact that they are positioned beneath the studs 74 and 76.

The non-add key 2% is secured to a stem 1.26 which, as best shown inFig. 2, is pivoted on a stud 128 and has a shouldered stud 130 securedthereto. This stud, as best shown in Fig. 8, projects through anelbow-shaped slot 132 formed in an arm 134 secured to a shaft 1%. The

lever shaft 100 extends transversely across the machine and,

as shown in Fig. 6, has the arm 98 secured thereto, this arm carryingthe stud 96 which, as previously described, engages a camming projection94 on the slide 32. When the non-add key is swung rearwardly, it earnsthe arm 134 upwardly, rotating the shaft 100 counterclockwise (Figs. 6and 8) and by virtue of the camming action of the stud against thesurface 94, the slide 32 is pushed forwardly, thus preventing operationof either the plus or minus key bars 22, 24. The stud 96 also engagesthe upper end 136 of the arm 92 and cams the latter rear- Wardly tocause the notch 124 to engage the stud 122 and thereby lock the totaland subtotal key against op eration. It will be noted, for example inFig. 6, that the upper end of the locking arm 78 and the camming surface86 lie under the stud 76 on the minus key stem 47, and that the upperend of the locking lever 73 also lies beneath the'stud 74.

Thus it will be clear that the total and subtotal key 26, the non-addkey 28, the plus bar 22, and the minus bar 24, are each interlocked withthe others so that operation of any one of these keys will prevent theoperation of the remaining keys.

It will berecalled that depression of either the plus bar 26 or theminus bar 24 will cause depression of the link 64 and closure of theswitch 72. The operation of the total and subtotal key and the non-addkey are also effective to close the switch 72. The total and subtotalkey 26 operates the switch through the mechanism in part previouslydescribed, namely, the arm 108, sleeve 112, arm 114, and crank 113. Thecrank 11% carries a roller 140 (Fig. 7) which rides along the curvededge 142 of a lever 144, the latter being pivoted on shaft 100 andhaving a bail portion 146 to steady it. The lever 144 has a downwardlyextending projection 148 which, when the lever swings clockwise (Fig. 7)engages a stud 150 which extends inwardly from an arm 152 mounted on astud 154. The arm 152 overlies a roller 156 mounted on the upper end ofthe link 64. The camming surface 142 is of such contour that the lever144 will be swung clockwise irrespective of whether the key 26 is pushedrearwardly to initiate a subtotal, or forwardly to initiate a totaltaking operation.

It will be apparent from Fig. 8 that the operation of the non-add key 28will cause counterclockwise movement of the shaft 100 and lever 98. Thelever 98 has an open end slot 158 for the reception of a stud 160carried on an arm 162 and pivoted on a stud 164. The forward edge of thelever 162 has carnming engagement with stud 150 and thus rotates the arm152 counterclockwise to depress the motor switch operating link 64.

Referring to Fig. l, the casing of the machine includes a base which hasthe usual rubber feet 172. A front casing part 174 is mounted on thebase'170 and a hood portion 176 of the casing is secured to the base 170by a hinge 178, this hood being provided with suitable open:

4 ings 180 for the keys 26 and 26. As best shown in Fig. 18, the hood176 has a downwardly and forwardly projecting arm 182 carrying a stud184 which rides in a slot 186 formed in a three-armed crank 18%. Themajor portion of the slot 186 is circular about the center of the pintleof hinge 178. The lower end of the slot is so shaped that upon initialupward swinging movement of the hood 176 the crank 188 is swungcounterclockwise, as shown in Fig. 18. The forwardly extending arm 192of the three-armed crank 183 has a disc 1% of insulating mate rimsecured thereto for the operation of a leaf spring switch 194. When thehood is in its normal lowered position, the disc 19% holds the switch194 closed, as shown in dotted lines in Fig. 1.

As shown in Fig. 19, the motor 30 is wired in series with speed governor32, motor switch 72, and the safety switch 194. An antispark capacitor1% is connected across switch 72 and a resistor 200 and capacitor 203are connected across the governor to reduce sparking at the contactpoints thereof. Thus when the hood is lifted and the switch 194 isopened, it will be seen from the circuit diagram of Fig. 19 that themotor cannot be started by operation of any of the keys.

In prior machines of this type, the operator might strike the total key26 a glancing blow to flip it to total taking position. In suchinstances the switch 72 might be closed to start the motor, but the keymight have returned to normal position before being locked in itsoperating position through operation of the machine. Such rapidoperation of the key would therefore result in merely a blank stroke. Inthe machine disclosed herein, such misoperation of the machine isprevented by providing a latch 202 (Figs. 9l2) pivoted on a stud 204 andhaving a sidewardly bent lug 206 for engagement with a tooth 2138forming part of key stem 102. When the key 26 is flipped forwardly tothe position shown in Fig. 10, or slightly beyond, the lug 206 engagesbehind the tooth 208 and prevents the key stem 1192 from being returnedto normal position by its return spring 105. In flipping the key 26forwardly slightly beyond the position in which it is shown in Fig. 10,the switch 72 is closed and it is latched in closed position by suitablemeans such, for example, as shown in T. O. Mehan Patent No. 2,362,709.

As the motor commences to rotate, a cam 212 on the main rock shaft 214engages a roller 216 carried by a lock plate 218 pivoted on a stud 220,and swings the lock plate 218 clockwise to the position in which it isshown in Fig. 11. In moving to this position, it will be noted that anear 222 forming part of the lock plate 218, engages a projection 224 onthe key stem 102 and swings the latter counterclockwise to its fullyoperated position. At the same time a projection 226 on the lock plate218 engages a stud 228 on the latch lever 202 and swings the lattercounterclockwise to a position such that a keeper lever 230 may be swungclockwise by a spring 232 and thereby cause a sidewardly bent lug 234 toengage in a notch 236 formed in the forward end of the latching lever202. Near the end of the return stroke of the rock shaft 214, the roller216 follows the cam surface and the locking plate is moved to theposition shown in Fig. 9, and thus releases the key stem 102 to permitthe latter to return to its normal central position. At the very end ofthe return stroke, a roller 238 engages a depending hook portion 240 ofthe lever230 and swings the latter slightly counterclockwise to free thelug 234 thereof from the notch 236 at the forward end of the latch lever202, whereupon all of the parts will be restored to the position inwhich they are shown in Fig. 9.

If, with the hood176 raised, the operator were to operate the key 26 asby swinging it forwardly for a total taking operation, the machine wouldnot start operating because the safety switch 124 would be open.However, the key might remain latched and thus prevent the hood frombeing lowered to its normal position, or damage the key. Means istherefore provided to prevent operation of the latch 202 whenever thehood is raised from its normal position. This means is best shown inFigs. 9 and 12, and comprises a slide 242 having elongated slots 243which encompass studs 244. The slide 242 is biased for upward movementby a tension spring 246. The slide is normally held in its lowerposition by the engagement of the hood 176 with the upper end of theslide. However, when the hood is raised the slide 242 is free to moveupwardly to the position shown in Fig. 12, and in sliding upwardly, apin 248 carried thereby engages beneath the rearwardly projecting arm oflatch lever 202 and swings the latter counterclockwise to prevent thislatch lever from having its lug 206 engage the tooth 208. The total keylatching, mechanism is thus disabled.

When a subtotal is to be taken, the key 226 is swung clockwise from theposition shown in Fig. 9, until the lug 206 on the latching lever 202engages behind a tooth 250 formed on the key stem 102. In other respectsthe mechanism shown in Figs. 9 to 12 operates, in preparing for thetaking of a sub-total, in the same manner as above described withreference to its operation for total taking.

It will be noted that the spring 105 is a centering spring and iseffective to return the key stem 102 to its central normal positionwhenever it is released by the latching mechanism.

It is desirable to register the character of the machine operation byprinting a signal indicating the type of operation beside the amount,except in the case of an adding operation, where no such signal isnecessary. The means disclosed herein for accomplishing this signalprinting is best shown in Figs. 13 to 17, and comprises a sector 260having a type segment 262 secured thereto bearing the letters T fortotal, N for non-add, for subtracted items, and an 8" for subtotal. Thepositions of these type are indicated by the legends in Fig. 13.

The sector 260 has an inverted T-shaped slot 264, best shown in Fig. 15.A pin 266 projects sidewardly from the lower end of the key stern 102into the slot 264, and also may engage in an open end slot 268 formed ina slide 270. This slide is guided for radial movement on the sector 260by a pin 272, which extends through an elongated slot 274, and by anelongated slot 276 which embraces the hub 277 of the sector 260. Thesector is normally urged to move in a clockwise direction by a ten-S1011 spring 278. The lower end of the slide 270 is provided with anarcuate slot 280 for the reception of a pin 282 carried at the rearwardend of a lever 284.

When the slide 270 is in the position in which it is of the slot 264 andthus if the key is swung forwardly, as for taking a total, the sector260 will be rocked counterclockwise With the key to bring the T typeinto printing position. Similarly, if the key 26 is swung rearwardly totake a subtotal, the subtotal type will be brought into printingposition, it being noted that the key stem 102 is pivoted on stud 104 sothat as the key is swung in one direction the sector 260 will be rotatedin the opposite direction.

A lever 287, pivoted on a stud 288, has its upper end 298 normally heldagainst a stud 292 on the minus key stem 47 by a tension spring 294.When the minus key is depressed (Fig. 16) the spring 294 pulls the lever286 clockwise, bringing the upper end of the lever 286 over the stud292, and thus holds the minus key 24 in its depressed position. Themotor is energized when the minus key is thus depressed, and the rockshaft 214 commences rotating counterclockwise. A plate cam 296 fixed onthis shaft engages a roller 298 carried at the end of an arm 300, andswings the arm in a clockwise direction. When the subtract key isdepressed and the lever 286 swings clockwise, a pin 302 on the latterengages the upper ear of a hook member 304 and swings the latter to theposition in which it is shown in Fig. 16. The hook member 304 is pivotedat the end of a bellcrank 306 shown in Fig. 13, the pin 266 is held inthe center portion which in turn is pivoted on a stud 308. The hookmemher 304 is biased to move toward the position in which it is shown inFig. 13, by a tension spring 310. The arm 306 is rigidly connected withan arm 312. Thus when the roller 298 is forced out of the notch in thecam plate 296, as the machine commences operating, the arm 300 will beswung downwardly, carrying the hook member 304 and the arms 306 and 312clockwise with it. A motion reversing lever 314 is pivoted on a stud316, and has a pin and open end slot pivotal connection with the arm312. The lever 314 has a stud 318 at its rearward end for engagementwith a forwardly projecting ear 320, which is part of a lever 321pivoted on a shaft 286.

The rearwardly extending portion of the lever 321 has two prongs 322 and323. As the lever 321 is swung clockwise, the prong 323 engages the pin282 and moves the slide 270 downwardly, thus freeing the sector forpivotal movement to the extent allowed by the horizontal portion of theinverted T-shaped slot 264. Thus the spring 278 would be free to swingthe sector 260 clockwise, were it not for the fact that the other prong322 of the lever 321 engages a stud 324 on the sector and forces thesector counterclockwise against the tension of spring 278 to bring theminus sign type in printing position.

After the calculating and printing operation has been completed, and asthe main rock shaft approaches its normal position, a stud 326 on theplate cam 296 engages a wipe pawl 328 and swings the lever 287counterclockwise, thereby releasing the minus key, which is returned toits normal position by its return spring 330, and permitting therestoration to normal position of all parts just described withreference to Fig. 13.

Referring to Fig. 14, when the non-add key 28 is swung rearwardly for anon-add operation, its key stem 126 pivots on a stud 128 and carries apin 332 which engages the upper end of a lever 334 pivoted on a stud336. The lower end of the lever 334 carries a pin 338 which operates inan open end slot 340 formed in a bail-shaped lever 342, 343, pivoted ona stud 344. The lever 342, 343 is thus swung counterclockwise and,through a pin and slot connection with the rearwardly extending arm 346of a suitably pivoted bellcrank, swings the latter clockwise. Theupwardly extending arm 347 of bellcrank 346, has a pin and slotconnection with an arm 348 fixed to the shaft 286, which, as best shownin Fig. 17, extends across the machine, and near its right-hand endcarries the lever 284. As viewed in Fig. 14, the movement of the shaft286 was in a counterclockwise direction, so that as viewed in Fig. 17,the rotation of the shaft 286 is in a clockwise direction, and thusthrough the pin 282 and cooperating slot 280 of the slide 270, thelatter is moved downwardly, freeing the sector 260 for clockwiserotation by its spring 278 to the extent permitted by the pin 266 andinverted T-shaped slot 264. This clockwise movement of the sector 260will bring the non-add signal type N in printing position. The means forholding the non-add key 20 in operated position during the machinecycle, is not disclosed herein, but may be of the type shown in thepatent to T. O. Mehan No. 2,411,050.

From the foregoing, it will appear that whenever one of the keys 22, 24,2G, or 28 is operated, the operation of the other keys of this group isprevented by means of the locking arm 78, the slide 82, or the arm 92,and that these keys are thus completely interlocked. Further, theoperation of the subtotal and total key 26 in either direction, theoperation of the minus key bar 24, or the operation of the non-add key,will index the type segment 262 to the proper position for imprintingthe correct signal character.

Due to the provision of the latching mechanism for the total andsubtotal key 26, as particularly shown in Figs. 9 to 12, rapid operationof the machine is made possible without undesired blank strokes, andfurther, this latching mechanism is disabled whenever the hood 176 israised, due to the provision of the slide 242. Likewise, the raising ofthe hood disables the driving motor by opening its energizing circuit,

" While we have shown and described a preferred embodiment of ourinvention, it will be apparent that numerous variations andmodifications thereof may be made without departing from the underlyingprinciples of the invention. We therefore desire, by the followingclaims, to include within the scope of the invention all such variationsand modifications by which substantially the results of our inventionmay be obtained through the use of substantially the same or equivalentmeans,

We claim:

1. In a calculating machine having an electric motor for driving thesame, a series circuit for energizing the motor and a switch in saidcircuit, the combination of an add key, a subtract key, a combined totaland subtotal key pivoted for forward and rearward movement from itsnormal position, a nonadd key, a stem for each of said keys, and meansoperable respectively by each of said keys for closing said switch, theswitch closing means operable by the total and subtotal key comprising alink with an insulating member mounted thereon for engagement with saidswitch to close the same, means for keeping said link normally out ofengagement with said switch, a sleeve rotatable by forward and rearwardmovement of the total and subtotal key, a crank adapted for beingreciprocated by rotation of the sleeve in opposite directions, a leverpivoted on a shaft within said sleeve and coaxial therewith, an armcooperable with the lever for moving said link into switch-closingposition upon movement of the lever toward the link, and a rollerattached to said crank for riding along a cammed edge of said lever,said edge being of such contour that the lever moves toward the linkindependently of the direction in which the total andsubtotalkey ismoved away from its normal position.

2. In a calculating machine having an. electric motor for driving thesame, a series circuit for energizing the motor and a switch in saidcircuit, the combination of an add key, a subtract key, a combined totaland subtotal key, a nonadd key pivoted for forward and rearwardmovement, a stem for each of said keys, and means operable respectivelyby each of said keys for closing said switch, the switch-closing meansoperable by the nonadd key comprising a link with an insulating membermounted thereon for engagement with said switch to close the same, meansfor keeping said link normally out of engagement with said switch, ashaft, a slotted arm secured to said shaft, a stud carried by the nonaddkey stem and projecting through and riding in the slot in said arm forrotation of the shaft upon operation of the nonadd key, a lever securedto said shaft and having a slotted end therein, a pivoted arm carrying astud in engagement with the slotted end of said lever, and a pivotedmember in camming engagement with the pivoted arm for moving said linkinto switch closing position upon rotation of the shaft when the nonaddkey is moved into nonadd position.

References Cited in the me of this patent UNITED STATES PATENTS1,925,089 Barrett Sept. 5, 1933 2,289,056 Landsiedel July 7, 19422,562,049 Lambert July 24, 1951 2,583,810 Boyden Jan. 29, 1952 r2,669,331 Dudis et a1. Feb. 16, 1954

